<meta charset="utf-8">
(#) Duplicate JSON names are errors as JSON does not allow duplicate keys in objects

!!! ERROR: Duplicate JSON names are errors as JSON does not allow duplicate keys in objects
   This is an error.

Id
:   `MoshiUsageDuplicateJsonName`
Summary
:   Duplicate JSON names are errors as JSON does not allow duplicate keys in objects
Severity
:   Error
Category
:   Correctness
Platform
:   Any
Vendor
:   slack
Identifier
:   slack-lint
Contact
:   https://github.com/slackhq/slack-lints
Feedback
:   https://github.com/slackhq/slack-lints
Min
:   Lint 8.7+
Compiled
:   Lint 8.7+
Artifact
:   [com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html)
Since
:   0.1.0
Affects
:   Kotlin and Java files and test sources
Editing
:   This check runs on the fly in the IDE editor
Implementation
:   [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/main/java/slack/lint/MoshiUsageDetector.kt)
Tests
:   [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/MoshiUsageDetectorTest.kt)
Copyright Year
:   2021

Duplicate JSON names are errors as JSON does not allow duplicate keys in
objects.

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
src/slack/model/Example.kt:8:Error: Name 'value' is duplicated by member
'anotherValue'. [MoshiUsageDuplicateJsonName]
  val value: String,
      -----
src/slack/model/Example.kt:9:Error: Name 'value' is duplicated by member
'value'. [MoshiUsageDuplicateJsonName]
  @Json(name = "value") val anotherValue: String,
                            ------------
src/slack/model/Example.kt:10:Error: Name 'value2' is duplicated by
member 'anotherValue3'. [MoshiUsageDuplicateJsonName]
  @Json(name = "value2") val anotherValue2: String,
                             -------------
src/slack/model/Example.kt:11:Error: Name 'value2' is duplicated by
member 'anotherValue2'. [MoshiUsageDuplicateJsonName]
  @Json(name = "value2") val anotherValue3: String
                             -------------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`src/slack/model/Example.kt`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers
package slack.model

import com.squareup.moshi.Json
import com.squareup.moshi.JsonClass

@JsonClass(generateAdapter = true)
data class Example(
  val value: String,
  @Json(name = "value") val anotherValue: String,
  @Json(name = "value2") val anotherValue2: String,
  @Json(name = "value2") val anotherValue3: String
)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/MoshiUsageDetectorTest.kt)
for the unit tests for this check to see additional scenarios.

The above example was automatically extracted from the first unit test
found for this lint check, `MoshiUsageDetector.duplicateNames`.
To report a problem with this extracted sample, visit
https://github.com/slackhq/slack-lints.

(##) Including

!!!
   This is not a built-in check. To include it, add the below dependency
   to your project. This lint check is included in the lint documentation,
   but the Android team may or may not agree with its recommendations.

```
// build.gradle.kts
lintChecks("com.slack.lint:slack-lint-checks:0.8.2")

// build.gradle
lintChecks 'com.slack.lint:slack-lint-checks:0.8.2'

// build.gradle.kts with version catalogs:
lintChecks(libs.slack.lint.checks)

# libs.versions.toml
[versions]
slack-lint-checks = "0.8.2"
[libraries]
# For clarity and text wrapping purposes the following declaration is
# shown split up across lines, but in TOML it needs to be on a single
# line (see https://github.com/toml-lang/toml/issues/516) so adjust
# when pasting into libs.versions.toml:
slack-lint-checks = {
    module = "com.slack.lint:slack-lint-checks",
    version.ref = "slack-lint-checks"
}
```

0.8.2 is the version this documentation was generated from;
there may be newer versions available.

[Additional details about com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html).
(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Using a suppression annotation like this on the enclosing
  element:

  ```kt
  // Kotlin
  @Suppress("MoshiUsageDuplicateJsonName")
  fun method() {
     problematicStatement()
  }
  ```

  or

  ```java
  // Java
  @SuppressWarnings("MoshiUsageDuplicateJsonName")
  void method() {
     problematicStatement();
  }
  ```

* Using a suppression comment like this on the line above:

  ```kt
  //noinspection MoshiUsageDuplicateJsonName
  problematicStatement()
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="MoshiUsageDuplicateJsonName" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'MoshiUsageDuplicateJsonName'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore MoshiUsageDuplicateJsonName ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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